Is In-Flight Oxygen for Pulmonary Hypertension Necessary?

After finding a high rate of symptoms among people with pulmonary hypertension during commercial air flights, Nareg Roubinian, C. Gregory Elliott, and Hubert Chen are recommending that everyone with significant pulmonary hypertension planning to take a flight longer than 2.5 hours should be evaluated for supplemental in-flight oxygen. They publish their findings in the October 2012 Chest.

They gave altimeters and pulse oximeters to 34 people with pulmonary hypertension prior to taking commercial flights. Patients were not hypoxic at rest at baseline, but had significant PH (60% with idiopathic pulmonary arterial hypertension; 90% WHO class II-III symptoms, 33% receiving prostacyclin infusion). Then, they boarded the planes, sans in-flight oxygen. Bon voyage!

What happened?

Half of the participants had at least a 5% (absolute) drop in oxygen saturation. However, only 9 of the 34 had significant hypoxemia (SaO2 < 85%), and 7 of those had already been prescribed at-home oxygen (nocturnal/exertional).

Oxygen desaturation occurred more often on flights longer than 2.5-3 hours and when cabin pressure was lower than FAA-mandated 8,000 feet (which happened surprisingly often).

38% (13 of 34) described symptoms including chest pressure/tightness, dyspnea, lightheadedness, and palpitations. Having symptoms did not correlate with desaturation, although the sample may have been too small to find this.

There were no medical emergencies or complications.

One-third of the participants reported having had pre-flight evaluation in the past, and a third had been prescribed in-flight oxygen before, suggesting many physicians were already thinking about the issue.

Evaluation for in-flight oxygen requires performing either the hypoxia altitude simulation test (HAST), or the gold standard of hypobaric chamber testing, which is less convenient and not widely available. Dillard et al found the HAST to correlate well with hypobaric testing, both in people with and without COPD. Resting oxygenation does not predict in-flight oxygen desaturation, and neither does FEV1 in people with COPD.